Online chat may refer to any kind of communication over the Internet that offers a real-time transmission of text messages from sender to receiver.

Chat messages are generally short in order to enable other participants to respond quickly.

Thereby, a feeling similar to a spoken conversation is created, which distinguishes chatting from other text-based online communication forms such as Internet forums and email.

Online chat may address point-to-point communications as well as multicast communications from one sender to many receivers and voice and video chat, or may be a feature of a web conferencing service.

Videotelephony comprises the technologies for the reception and transmission of audio-video signals by users at different locations, for communication between people in real-time.

A videophone is a telephone with a video display, capable of simultaneous video and audio for communication between people in real-time.

Videoconferencing implies the use of this technology for a group or organizational meeting rather than for individuals, in a videoconference.

Telepresence may refer either to a high-quality videotelephony system (where the goal is to create the illusion that remote participants are in the same room) or to meetup technology, which goes beyond video into robotics (such as moving around the room or physically manipulating objects).

Videoconferencing has also been called "visual collaboration" and is a type of groupware.

Anonymity, adjective "anonymous", is derived from the Greek word ἀνωνυμία, anonymia, meaning "without a name" or "namelessness".

In colloquial use, "anonymous" is used to describe situations where the acting person's name is unknown.

Some writers have argued that namelessness, though technically correct, does not capture what is more centrally at stake in contexts of anonymity.

The important idea here is that a person be non-identifiable, unreachable, or untrackable.

Anonymity is seen as a technique, or a way of realizing, a certain other values, such as privacy, or liberty.